There also may be economic reasons for the shift, McGuckin's research indicates. Employment of 16- to 24-year-olds as a share of all workers has declined. At the same time, the rate of young men ages 18 to 34 years old living at home has been going up and is greater than the rate of young women living at home.
It may be that unemployment and underemployment have made auto insurance unaffordable for young men, said Alan Pisarski, author of the Transportation Research Board's comprehensive "Commuting in America" reports on U.S. travel trends. "Insurance for males under 25 is just colossally expensive," he said.
There has also been a sharp decline in vehicle trips and the number of miles traveled by vehicle for 16- to 29-year old males, according to McGuckin's analysis of massive government travel surveys between 1990 and 2009. The declines for women were not as great.
"The car companies are very worried," she said.Gloria Berquist, vice president of the Alliance of Automobile Manufacturers, said the alliance is aware that the share of teens and young adults obtaining driver licenses is dropping, although the association hasn't seen the research on the gender differences. "Some research has shown that young adults today connect with their friends through their smartphones, but at some point younger consumers still need to get from here to there, and a car is still a priority where public transportation is unavailable or limited," she said. "This is especially true for younger adults when they enter the workforce." ___ Follow Joan Lowy at http://www.twitter.com/AP_Joan_Lowy